Although gene products that regulate apoptosis appear to be excellent targets for therapeutic intervention in alleviating disease processes, few therapeutics currently exit. Furthermore, there are no rapid, in vivo assays for screening potential candidate molecules in a vertebrate system. Phase I research proposes to develop an apoptosis assay using zebrafish (danio rerio) as a model system. Although mouse is a powerful genetic model, the ability to study phenotypic changes, such as apoptosis, is hampered by its lengthy in utero development. A major strength of zebrafish is that it is transparent and completes morphogenesis in 72 hours, making it highly accessible to manipulation and observation and amenable to eventual high throughput automation. PROPOSED COMMERCIAL APPLICATION: Use of zebrafish as a model for drug screening will significantly improve therapeutic development. Zebrafish is a vertebrate and lends itself to automated bioassay of chemical libraries estimated to be a $500 million market.